The invention relates to an unlocking prevention device for a vehicle steering wheel lock of the type having a locking detent bolt actuable by means of a locking cam surface on a locking cylinder.
German Patent Specification No. 3,131,558 describes a steering lock for motor vehicles, in which a detent pin can be blocked in its locking position by a spring-loaded detent piece during the unauthorized removal of the locking cylinder. This detent piece is controlled by a wire fastened to the locking cylinder. A problem which arises in a design of this type is that the wire is parallel to the detent pin which is pulled back during each unlocking operation and which, when it comes into contact with the wire, endeavors to pull this along with it. During the next locking operation, with the wire being taken up the detent piece would drop in, and the detent pin would then be permanently locked unintentionally and the vehicle consequently no longer steerable.
To avoid this danger, it is desirable to prevent the wire from making contact by means of guide ducts or spacers which entail a high outlay in terms of cost in this inaccessible region.
An object of the invention is to improve the above-noted prior arrangement and provide for actuation of an unlocking prevention device for a steering wheel lock for motor vehicles solely as a result of the unlawful opening of the locking system.
This object is achieved by providing shifting force means to shift the locking cylinder shaft toward a detent locking position and to provide means on the locking cylinder shaft and detent pin to prevent lifting of the detent pin when the shaft is in the shifted position.
Because the shaft is shifted after the lock housing has been broken off or unlawfully removed when the detent pin is in the locking position, the detent pin driver is disengaged from the actuating locking cam and thus, like the detent pin, remains in the locking position. The steering wheel lock is blocked reliably against further manipulation because the detent pin driver drops into a shaft groove.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.